EN language
  • PT
  • ES
Foto da SE Barreiras II - Jalapão da Neoenergia

The path of electricity, from generation to distribution

9/20/24

The energy that reaches Brazilian homes and industries doesn't just magically appear - it has to travel along a path full of complex stages and technologies. From generation to distribution, each stage plays an important role in ensuring that it is efficient, sustainable and uninterrupted. Understand how this happens. 

What is electricity?

In physics, energy is defined as the ability to perform an action, such as moving or heating objects. One of the best-known forms of energy is electrical energy - or electricity - which is the flow of electrical charges, whether positive or negative.

All materials are made up of molecules, which in turn are made up of atoms. These atoms have smaller particles, such as neutrons, protons and electrons. When these particles move, they naturally generate electrical charges.

When this flow of charges occurs in an organized way inside a conductor, between two poles, an electric current is formed. This is how electronic devices work.

How was electricity discovered?

Electricity was discovered in the 6th century BC by the Greek philosopher Thales of Miletus, who, when rubbing amber with silk and other objects, noticed that it became charged and attracted them. Since the 1600s, scientists and inventors have carried out various experiments that gave rise to the current model, perfecting the process throughout history.

In 1752, Benjamin Franklin stated that lightning is electricity. Over the next century, various models of light bulbs, generators and batteries were created. In 1879, Thomas Edison invented a light bulb that could be used for around 40 hours without burning out, the first commercially viable one, and then installed a power plant to sell electricity to his customers. The transmission problem was solved by Nicola Tesla in the following decades, expanding the use of electricity.

Today, it can be used for a variety of purposes, from household appliances to powering machinery in factories. In Brazil, industry is the biggest consumer, followed by households, according to figures from the Anuário Estatístico da Energia Elétrica.

The first Brazilian hydroelectric plant was built in 1889 in Minas Gerais. In the following years, cities such as Rio de Janeiro and Porto Alegre received public lighting services and electric streetcars.

What are the forms of energy?

French chemist Antoine Lavoisier is known for the Principle of Conservation of Mass, which he summed up in the famous phrase: "In nature, nothing is created, nothing is lost, everything is transformed". This also applies to the electricity we use every day, since it is generated from other forms of energy: potential and kinetic.

  • Potential Energy: is stored energy, ready to be used. 


  • Kinetic energy: energy in motion, capable of exerting force and moving objects. 

An example of how they work can be seen in hydroelectric plants, which generate much of the electricity that supplies Brazil. River water has potential energy and, when it moves in a cascade, this energy is transformed into kinetic energy, which makes the plant's turbines move. Then a piece of equipment called a generator converts it into electricity.

 

How does the electricity system work in Brazil?

In Brazil, electricity passes through three main stages until it reaches the end consumer: generation, transmission and distribution - and these are carried out by public and private companies, which operate through concessions obtained in auctions regulated by the National Electricity Agency (Aneel).

Aneel establishes norms and guidelines to ensure that these institutions are remunerated appropriately, ensuring the efficiency and continuity of the energy service in the country.

In addition, a large part of Brazil's energy is connected to the National Interconnected System (SIN), a network that integrates most generating plants with transmission lines. The SIN covers almost the entire national territory and allows energy to be transported efficiently between the different regions.

This means that if a region is generating more energy than it consumes through the SIN, the surplus can be transferred to other areas, balancing supply and demand in the country. However, there are still around 250 isolated areas, such as the Fernando de Noronha archipelago (PE) and various regions in the Amazon, which are not part of the SIN and operate independently, with isolated systems.

In order to understand the complete functioning of the electricity system, it is necessary to know how these phases work and how they contribute to the energy that is delivered to the end consumer:

Energy generation

Energy can be generated from various sources, such as river water, wind, the sun and natural gas. In Brazil, most of the electrical matrix, which is the set of resources used to meet the country's demand, is clean and renewable.

Hydroelectric plants are the country's main source of energy, harnessing the power of rivers to move turbines and generate electricity, but wind power is also gaining ground.

Brazil has great potential for this type of generation, especially in the Northeast, due to the region's strong and constant winds. Another source that is also growing in the country is solar power, due to the excellent solar irradiation conditions in Brazil. It is expected to surpass hydroelectric power by 2040. 

How is energy generated?

The process of generating electricity varies according to the source used:

Hydroelectric:

In hydroelectric power stations, water is stored in large reservoirs. When it is released, it forces the turbine blades to move and rotate, thus producing energy.

 

Wind

In wind farms, large wind turbines are installed in areas with strong, constant winds. These winds cause the propellers to move and generate electricity.

 

Solar

Solar energy is captured by a technology called photovoltaic solar panels, which convert sunlight directly into electricity.

The National Electricity System Operator (ONS) is the body responsible for managing these resources, planning needs and activating power plants from each source to generate enough energy to meet all demand.

                                                      Curiosity
In addition to large power plants, distributed generation (DG) is on the rise, where production takes place on a small scale, either through photovoltaic systems installed on the roofs of homes and businesses or in small parks. In these cases, the energy can serve the property itself or generate credits on the electricity bill.

 

Energy transmission

After being generated at the power plants, the energy is sent to substations, where transformers raise the voltage of the grid, allowing it to be sent through the transmission lines. These lines, made up of cables and metal towers, are installed in strategically selected locations to connect generators to consumption centers, crossing highways, rural areas and even rivers.

The country has a basic transmission network of around 175,000 kilometers, passing through all the states and the Federal District. Interconnection via these lines allows for the transfer of energy, which has advantages such as safety, operational synergy and the possibility of making efficient use of different hydrological regimes.

Why is electricity transmitted at high voltage?

Electricity is transmitted at high voltage to ensure that electricity can be transported over long distances efficiently, with as little energy loss as possible.

In the National Interconnected System, this voltage can exceed 230,000 volts. When the electricity reaches the centers of consumption - such as cities and industries - this voltage is reduced again to lower levels (110 or 220 volts) by other transformers in the distribution stage, in order to reach the consumer.

Distribution

Distribution is the stage that ensures that energy reaches homes, businesses, industries, commercial establishments and streetlights. In other words, the day-to-day life of the end customer. In Brazil, there is a distribution service concession system, in which public and private companies manage the supply in accordance with Aneel standards.

The concessionaires that carry out this distribution are responsible for ensuring that the energy, after passing through transmission, is delivered to the consumer safely and continuously. To do this, they use a complex network of poles, transformers and cables that connect substations to properties.

The work of these companies goes beyond supplying energy, and also includes maintaining the network, solving problems and extending the infrastructure to new areas.

Energy trading

Energy trading is the stage in the electricity system where the energy generated by power plants is bought and sold before it reaches the end consumer. In Brazil, this trading takes place in two main ways: in the Regulated Contracting Environment (ACR) and in the Free Contracting Environment (ACL).

  • Free Contracting Environment (ACL): A modality where consumers freely choose their electricity suppliers. In this environment, consumers and suppliers can negotiate commercial conditions, such as price, quantity of energy contracted, supply period, payment date, among others, providing consumers with significant savings.
  • Regulated Contracting Environment (ACR): Buying and selling energy in a standardized way and regulated by the government. Energy distributors take part in public auctions to acquire the energy they will distribute, at a price set and regulated by Aneel. In this system, the end consumer cannot choose their energy supplier, being served exclusively by the distributor responsible for their region.

Despite the advantages, the ACL is still restricted to consumers with minimal energy demand, and is more attractive to industries and large companies. But the trend is for this modality to expand progressively and reach more customers around the country. There are discussions about opening up the market completely, which will allow residential consumers and small businesses to also choose their suppliers.

 

Find out more about Neoenergia's operating segments:

News